Multiple rotary switch circuit



April 26, 1960 J. w. GooTHI-:RTS 2,934,704

MULTIPLE ROTARY swITcH CIRCUIT Filed Aug. 18, 1958 51u/ rami,

' fam/frs' United States Patent O 2,934,104 MULTIPLE ROTARY SWITCHCIRCUIT Jerome W. Gootherts, Redwood City, Calif., assigner to AmericanRadiator & Standard Sanitary Corporation, New York, l\I.Y., acorporation of Delaware Application August 18, 1958, Serial No. 755,793

4 Claims. (Cl. 324-173) 'I'his invention relates to and in general hasfor its object the provision of a multiple rotary switch circuit wherebythe value of a plurality of resistors or functions thereof inserted inthe circuit can be successively sampled.

More specifically, the object of this invention is the provision of acircuit of the character above described wherein the m contact pointsofthe stator of a rst rotary switch are connected with the n contactpoints of the stator of a second rotary switch through mn uniquecircuits; wherein each of said mn circuits includes a resistor to besampled in series with a rectifier such as a diode; wherein a source ofvoltage and a current measuring device are connected in series acrossthe two rotary switching arms of the irst and second rotary switches;and wherein means is provided for rotating said switching arms at speedsin the inverse ratio of mm whereby said rotary switches servesuccessively to close each of said mn unique circuits, and each of theresistors in said circuits can be sampled once during each cycle ofoperation of the multiple rotary switch circuit.

Still another object of this invention is the provision of a switchingsystem for successively closing mn unique circuits across a first rotaryswitch provided with m contact points and a second rotary switchprovided with n contact points, and which can be substituted for asingle rotary switch having mn contact points.

Thel invention possesses other advantageous features, some of which,with the foregoing, will beset forth at length in the followingdescription where .that form of the invention which has been selectedfor illustration in the drawings accompanying and forming apart of thepresent specification, is outlined in full. In said drawings, one formof the invention is shown, but it is to be understood that it is notlimited to such form, since the invention as set forth in the claims maybe embodied in other forms.

Referring to the drawings,

Fig. l is a schematic diagram of a circuit or system embodying theobjects of my invention.

Fig. 2 is a time diagram of the circuit or system illustrated in Fig. lshowing the differential commutating action of the two rotary switchesof my system.

As illustrated in Fig. 1, the objects of my invention have been embodiedin a circuit or system including a iirst rotary switch S1 and a secondrotary switch S2. Included in the switch S1 is a conventional ring ofthree equally spaced contact points p1, p2, p3 and a first coaxialswitching arm A1 arranged to sweep over said contacts 1, 2, and 3.

Similarly, the second switch S2 includes a stator provided with a ringof four equally spaced contact points q1, q2, qs, and q., and a secondcoaxial switching arm A2.

Connected in series across the iirst and second switch arms A1 and A2 isa source of voltage V, and a current measun'ng device M, including aresistor Ro in parallelism with a cathode ray oscilloscope CRO.

Connected across the three contact points p1, p2, and p3 and the fourcontact points q1, q2, q3, and q., are

2,934,704 Patented Apr. 26, 1960 twelve unique circuits C1-C12,respectively including one of the resistors R1R12 to be sampled and eachincluding a rectifier here shown in the form of a diode d. Here isshould be noted that twelve circuits are involved for the reason thatthe three contact points of the first switch can be combined with thefour contact points of the second switch in twelve different anddistinct ways. More generally stated, m differentv objects or contactpoints can be combined with n different objects or contact points mndifferent ways or circuits.

Operatively associated with each of the rotary switching arms A1 and A2,through a gear reduction box G, is a'motor M1 for respectively drivingthe switching arms A1 and A2 in the inverse ratio of 4:3, or moregenerally stated, in the inverse'ratio of rz/m where m represents thenumber of contact points of switch S1 and n represents the number ofcontact points of switch S2.

As a result of this system, and with the switching arm A1 and A2initially set so that A1 is in contact with contact point p1, and A2 isin contact with q1, the two switches will serve to sequentially closethe circuits C1-C12, each of which, as shown in Fig. l, includes thesource of voltage V and the current measuring device M. This then makesit possible to sequentially sample each of the twelve resistors R1-R12,or in the more general case, the mn resistances.

The specific manner in which the two switches S1 and S2 cooperate witheach other so successively close the twelve unique circuits C1-C12 isdiagrammatically indicated in Fig. 2. From this figure it will be notedthat when switch S1 has completed one revolution, switch S2 hascompleted only three-fourths of a revolution, and that when S1 hascompleted four revolutions S2 has completed three revolutions, and thesystem has one cornplete cycle of operation in T seconds and is in aposition to repeat the cycle of operation.

The function of the rectiiiers or diodes d is of course to provide foronly unidirectional travel of the current passing through the circuitsC1-C12 and to thus provid for twelve unique sampling circuits. f

The system here illustrated can be extended to a pair of rotary switcheseach having any number of contact points m and n, respectively, but hereit should be noted that mn unique circuits can be obtained only providedthat m and n have no common factor other than the number one. If m and ndo have a common factor k, then the number of unique circuits per cycleof operation is reduced to mn/k. One way of insuring that m and n haveno co-mmon factor is to let n=m+1.

If S1 has 100 contact points and S2 has 101 contact points, and thecycle time is l/ minute (or the cyclic rate is 100 cycles per minute),then S1 runs at l0l l00=l0,100 r.p.m. and S2 runs at 10,000 rpm., andthe total number of resistances R sampled is 10,100. The output of CROlooks like the output of a 10,100 contact switch running at 100 rpm.

The resistors R can of course be replaced by other circuit elements orby Voltage or' current sources without changing the operation of thesystem, and for this reason the term resistor is here used in a genericsense to cover all such elements.

Finally, it should be noted that the switching arms of the two rotaryswitches can be driven from a single motor provided with power take-offsof the proper gear ratlos as above described.

I claim:

l. A multiple rotary switch system comprising: a first rotary switchhaving a first ring of m equally spaced contacts and provided with afirst coaxial switch arm arranged to sweep over said iirst ring of mcontacts; a second rotary switch having a second ring of n equallyspaced contacts and provided with a second coaxial switch arm arrangedto sweep over said second ling of n contacts; mn separate circuitsconnecting said m contacts with said n contacts, each of said mncircuits including a rectier; and rneans for simultaneously rotatingsaid iirst and second switch arms respectively at speeds` in the ratioof nrm.

2. A multiple rotary switch system of the character defined in clairn 1wherein n and m have no common factor.

3. A multiple rotary switch system comprising: a rst rotary switchhaving a first ring of m equally spaced contacts and provided with a rstcoaxial switch arm arranged to sweep over said rst ring of m contacts; asecond rotary switch having a second ring of n equally spaced contactsand provided with a second coaxial switch arm arranged to sweep oversaid second ring of n contacts; mn unique circuits connecting the mcontacts of References Cited in the le of this patent UNITED STATESPATENTS 2,264,623 Dickinson Dec. 2, 1941 2,460,835 Lutz Feb. 8, 19492,476,066 Rochester July 12, 1949 2,849,678 Hannon Aug. 26, 1958

